- Preheat oven to 400°F (200°C). Wrap whole beets in foil and bake until tender, about 45 minutes. 
- Allow beets to cool, then peel and slice into rounds or strips. 
- Heat oil in a large skillet over medium heat. Add minced garlic and sliced red onion, sauté for 2-3 minutes. 
- Add chopped kale to the skillet and cook until soft and wilted, about 5 minutes. 
- Warm tortillas in a dry skillet or microwave until pliable. 
- Assemble tacos by layering beet slices, sautéed kale mixture, avocado slices, jalapeño, and cilantro in tortillas. 
- Serve immediately with lime wedges or salsa if desired.